code: def __init__(self):
      self.sent_msg = defaultdict(dict)
      self.responded_messages = defaultdict(dict)
      self.deployments_called = []
  
imports: import asyncio
  import copy
  from collections import defaultdict
  from typing import List
  import pytest
  from docarray import Document, DocumentArray
  from jina.serve.runtimes.gateway.graph.topology_graph import TopologyGraph
  from jina.types.request import Request
  from jina.types.request.data import DataRequest
label_desc: Use image node_id 1 to create a new DummyMockConnectionPool object  with example: obj = DummyMockConnectionPool()